Evaluating a Targeted Minimum Loss-Based Estimator for Capture-Recapture Analysis: An Application to HIV Surveillance in San Francisco, California.

The capture-recapture method is a common tool used in epidemiology to estimate the size of "hidden" populations and correct the underascertainment of cases, based on incomplete and overlapping lists of the target population. Log-linear models are often used to estimate the population size yet may produce implausible and unreliable estimates due to model misspecification and small cell sizes. A novel targeted minimum loss-based estimation (TMLE) model developed for capture-recapture makes several notable improvements to conventional modeling: "targeting" the parameter of interest, flexibly fitting the data to alternative functional forms, and limiting bias from small cell sizes. Using simulations and empirical data from the San Francisco, California, Department of Public Health's human immunodeficiency virus (HIV) surveillance registry, we evaluated the performance of the TMLE model and compared results with those of other common models. Based on 2,584 people observed on 3 lists reportable to the surveillance registry, the TMLE model estimated the number of San Francisco residents living with HIV as of December 31, 2019, to be 13,523 (95% confidence interval: 12,222, 14,824). This estimate, compared with a "ground truth" of 12,507, was the most accurate and precise of all models examined. The TMLE model is a significant advancement in capture-recapture studies, leveraging modern statistical methods to improve estimation of the sizes of hidden populations.

Extending repair in peer interaction: A conversation analytic study.

Peer interaction constitutes a focal site for understanding learning orientations and autonomous learning behaviors. Based on 10 h of video-recorded data collected from small-size conversation-for-learning classes, this study, through the lens of Conversation Analysis, analyzes instances in which L2 learners spontaneously exploit learning opportunities from the on-task public talk and make them relevant for private learning in sequential private peer interaction. The analysis of extended negation-for-meaning practices in peer interaction displays how L2 learners orient to public repair for their learning opportunities in an immediate manner and in so doing, how different participation framework is being utilized to maximize their learning outcomes. As these extended repair practices are entirely managed by learners themselves, they yield both efficient and inefficient learning outcomes. Findings reveal that learners frequently resort to their peers to recycle the focal trouble words for learning opportunities, shifting their participating role from the on looking audience to active learners. By reporting the rather under-researched post-repair negotiation-for-meaning sequence in peer interactions, the study highlights the relevance between on-task classroom activities and private learning, contributing to understanding private learning behaviors in the language classroom and learning as a co-constructed activity locally situated in peer interaction.

Differential expression of VEGFR2 protein in HER2 positive primary human breast cancer: potential relevance to anti-angiogenic therapies.

BACKGROUND: Clinically relevant predictive biomarkers to tailor anti-angiogenic therapies to breast cancer (BRC) patient subpopulations are an unmet need. METHODS: We analyzed tumor vascular density and VEGFR2 protein expression in various subsets of primary human BRCs (186 females; Mean age: 59 years; range 33-88 years), using a tissue microarray. Discrete VEGFR2+ and CD34+ tumor vessels were manually scored in invasive ductal, lobular, mixed ductal-lobular and colloid (N = 139, 22, 18, 7) BRC cores. RESULTS: The observed CD34+ and VEGFR2+ tumor vascular counts in individual cases were heterogeneous. Mean CD34+ and VEGFR2+ tumor vessel counts were 11 and 3.4 per tumor TMA core respectively. Eighty-nine of 186 (48%) cases had >10 CD34+ tumor vessels, while 97/186 (52%) had fewer CD34+ vessels in each TMA core. Of 169 analyzable cores in the VEGFR2 stained TMA, 90 (53%) showed 1-5 VEGFR2+ tumor vessels/TMA core, while 42/169 (25%) cores had no detectable VEGFR2+ tumor vessels. Thirteen of 169 (8%) cases also showed tumor cell (cytoplasmic/membrane) expression of VEGFR2. Triple-negative breast cancers (TNBCs) appeared to be less vascular (Mean VD = 9.8, range 0-34) than other breast cancer subtypes. Overall, VEGFR2+ tumor vessel counts were significantly higher in HER2+ as compared to HR+ (p = 0.04) and TNBC (p = 0.02) tissues. Compared to HER2- cases, HER2+ breast cancers had higher VEGFR2+ tumor vessel counts (p = 0.007). CONCLUSION: Characterization of pathologic angiogenesis in HER2+ breast cancer provides scientific rationale for future investigation of clinical activity of agents targeting the VEGF/VEGFR2 axis in this clinically aggressive breast cancer subtype.

Results of a metabolic health clinic at a hostel for homeless men.

OBJECTIVES: People who are homeless have high mortality and morbidity, including from metabolic disorder. The aim of this study was to report on the characteristics and progress of the metabolic health of people attending a metabolic clinic at a homeless men's shelter. METHODS: Homeless men attending the clinic were assessed by measuring their weight, height, body mass index (BMI), waist circumference, blood pressure, blood lipids, fasting blood glucose and, if indicated, HbA1c. The sample characteristics of people who attended once (one-off clients) were compared to those who attended on more than one occasion (returning clients). Changes in health status were examined among returning clients by comparing baseline results to those at their last clinic visit. RESULTS: Baseline data were recorded on a total of 136 men, of whom 126 had a consultation with a general practitioner and at least one blood test. The 136 clients had a median BMI of 27.4 kg/m2. Forty-three were obese (BMI ≥30 kg/m2), 18 had class II obesity (BMI >35 kg/m2) and seven were underweight (BMI <20 kg/m2). Sixty-five had an intervention for either a newly diagnosed condition or a change to existing medical treatment. Seventy-six returning clients were seen on an average of 2.3 further occasions. Returning clients had significant improvements in measures of metabolic health. CONCLUSIONS: Homeless people in Sydney appear to be at a high risk of metabolic disease. The feasibility of a metabolic health clinic was demonstrated, and an encouraging improvement in some health indicators was found.

Kinase suppressor of Ras (KSR1) modulates multiple kit-ligand-dependent mast cell functions.

The intricately regulated Ras pathway coordinates multiple kit-ligand-induced mast cell functions, including chemotaxis, proliferation, and degranulation. However, the intracellular proteins that modulate the intensity and duration of stem cell factor-induced signals and the consequent cellular response are incompletely understood. Scaffolding proteins coordinate the spatial organization of mitogen-activated protein kinase proteins that may potentiate and/or inhibit cell functions. The kinase suppressor of Ras (KSR1) protein is known to function as a molecular scaffold and coordinates the organization of Raf/Mek/Erk in response to receptor tyrosine kinases. However, the impact of KSR1 in myeloid mast cell functions and in response to stem cell factor remains unknown. In the present study, we investigated the role of KSR1 in regulating cellular functions of bone marrow-derived mast cells of KSR1-deficient ((-/-)) mice. Genetic disruption of KSR1 resulted in both striking reductions in kit-ligand-mediated proliferation and degranulation, which are commonly attributed to mitogen-activated protein kinase signals. Surprisingly, disruption of the KSR1 scaffold also resulted in a decline in migration that is generally not linked to Raf-Erk signals. We found that loss of KSR1 does impact the biochemical activation of p21-activated kinase, a kinase that is known to modulate Raf-Erk signals and also F-actin polymerization key to mast cell migration. Collectively, these studies demonstrate that the scaffolding protein KSR1 has an important role in multiple kit-ligand-mediated mast cell functions. This study elucidates varied mast cell physiological functions for KSR1, including those related to cytoskeletal organization, and it suggests a novel molecular target for attenuating mast cell-mediated inflammation.

Genetic disruption of the scaffolding protein, Kinase Suppressor of Ras 1 (KSR1), differentially regulates GM-CSF-stimulated hyperproliferation in hematopoietic progenitors expressing activating PTPN11 mutants D61Y and E76K.

Activating PTPN11 mutants promote hematopoietic progenitor hyperactivation of Erk and hypersensitivity to GM-CSF. We hypothesized that Kinase Suppressor of Ras 1 (KSR1) contributes to activating PTPN11-induced GM-CSF hypersensitivity. Bone marrow progenitors from WT and KSR1-/- mice expressing WT Shp2, Shp2E76K, or Shp2D61Y were evaluated functionally and biochemically. KSR1 activation and interaction with phospho-Erk was enhanced in Shp2D61Y- and ShpE76K-expressing cells. Genetic disruption of KSR1 partially normalized Shp2E76K-induced GM-CSF hypersensitivity, but failed to correct Shp2D61Y-induced GM-CSF hypersensitivity. Collectively, these studies suggest that cells expressing Shp2E76K have a greater dependence on KSR1 for GM-CSF hypersensitivity than cells expressing Shp2D61Y.

Nf1-/- Schwann cell-conditioned medium modulates mast cell degranulation by c-Kit-mediated hyperactivation of phosphatidylinositol 3-kinase.

Neurofibromatosis type 1 (NF1) is a common genetic disorder and is characterized by both malignant and nonmalignant neurofibromas, which are composed of Schwann cells, degranulating mast cells, fibroblasts, and extracellular matrix. We and others have previously shown that hyperactivation of the c-Kit pathway in an Nf1 haploinsufficient microenvironment is required for both tumor formation and progression. Mast cells play a key role in both tumorigenesis and neoangiogenesis via the production of matrix metalloproteinases, heparin, and a range of different growth factors. In the present study, we show that tumorigenic Schwann cells derived from Nf1(-/-) embryos promote increased degranulation of Nf1(+/-) mast cells compared with wild-type mast cells via the secretion of the Kit ligand. Furthermore, we used genetic intercrosses as well as pharmacological agents to link the hyperactivation of the p21(Ras)-phosphatidylinositol 3-kinase (PI3K) pathway to the increased degranulation of Nf1(+/-) mast cells both in vitro and in vivo. These studies identify the p21(Ras)-PI3K pathway as a major regulator of the gain in Nf1(+/-) mast cell degranulation in neurofibromas. Collectively, these studies identify both c-Kit and PI3K as molecular targets that modulate mast cell functions in cases of NF1.